BACKGROUND:
As no evidence-based treatment guidelines exist for chronic Achilles tendon rupture (CATR), a systematic review of the literature was performed to compare the different treatment options and recommend a literature-based algorithm.

METHODS:
In June 2022, MEDLINE, Embase, and Cochrane Library databases were systematically reviewed based on the PRISMA guidelines. The level of evidence (LOE) and quality of evidence were evaluated, and statistics on clinical outcomes and complications were calculated.

RESULTS:
Twenty-seven studies with 614 patients were included. Three studies were LOE III and 25 studies were LOE IV. The mean Achilles tendon rupture score improved from a preoperative weighted mean of 38.8 ± 12.4 to a postoperative score 90.6 ± 4.7. The overall complication rate was 11.4%. Single techniques were used in 23 studies and dual techniques were used in 5 studies. The FHL tendon transfer was the most frequently used technique. We devised an algorithmic approach based on time from injury to surgical intervention and the length of the gap between the tendon stumps: >3 months: FHL transfer; < 3 months (a) gap < 2 cm, end-to-end repair; (b) gap 2 to 5 cm, gastrocnemius transfer, (c) gap >5 cm, semitendinosus autograft.

CONCLUSION:
Surgical management of CATR produced improvements in patient-reported outcome scores at midterm follow up, but a high complication rate (11.4%) was noted. Our proposed treatment algorithm may assist in shared decision making for this complex problem.